Tamperproof seal and method of production



Feb. 22, 1938. R 2,108,942

TAMPERPROOF SEAL AND METHOD OF PRODUCTION Filed March 13, 1935 2Sheets-Sheet 1 Feb. 22, 1938. R s R E 2,198,942

TAMPERPROOF SEAL AND METHOD OF PRODUCTION Filed March 15, 1935 2Sheets-Sheet 2 Patented Feb. 22, 1938 UNITED STATES awash FATENT QFFECERalph S. Peirce, Hinsdale, 111.

Application March 13, 1935, Serial No. 10,775

6 Claims.

This invention relates to tamper-proof seals or the like and method ofproduction.

Particularly on gas and. electric service meters, for example, which areintended to be sealed against unlawful access, it is important that theseals not only be such that they cannot be removed and replaced withoutbeing broken, but also that unauthorized or so-called bootleg seals benot substituted for the original seal after the first has been destroyedand unauthorized access had to the meter.

Among other objects, my invention aims to provide an improved seal andmethod of producing the same which meets both of these requirements andwhich can be produced in large quantities at extremely small individualcost.

The invention will be understood by reference to the accompanyingdrawings illustrating one form of seal made in accordance with myinvention and illustrative expedients for producing same in accordancewith the method of my invention.

In the drawings, Figure 1 is a fragmentary view of simple but practicaleXpedients, parts being shown in section, for practicing a preferredearly step in my invention, the expedients being shown in separatedrelation prior to the performance of the step.

Figure 2 shows a view of the expedients of Figure 1 in cooperativerelationship, other parts being shown in section;

Figure 3 is a similar view, partly in section, but subsequent to theperformance of a succeeding step;

Figure 4 shows the results of the performance of the steps indicated bythe previous figures;

Figure 5 shows the introduction of a malleable member of the seal, shownin section, and one means, also shown in section, for forming themalleable member in accordance with the invention;

Figure 6 shows a preferred operation on the malleable member inaccordance with my invention;

Figure '7 shows a completed seal made by the performance of the stepsindicated by the previous figures, the malleable member of the sealbeing shown in section and the flexible member partly in full and partlyin broken lines, indicating one relationship of parts;

Figure 8 is a view of the seal of Figure 7 on a larger scale, inperspective, associated with an object to be sealed;

Figure 9 is a view of the seal of Figure 8 after compression;

Figure 10 is a cross-section taken on the line iii-ill of Figure 6 on alarger scale;

Figure 11 is a cross-section taken on the line il-H of Figure 1 on alarger scale; and

Figure 12 is a cross-section taken on the line E2-i2 of Figure 2 on alarger scale.

Referring in detail to the figures of the drawings, I have shown apin-like mandrel ill having an enlarged shank I l by which the mandrelis supported by any suitable holder 52 having, in this instance, a borel3 receiving the cylindrical shank ii of the mandrel with the shoulderi=2 between the shank and the mandrel proper, and the mandrel itself,projected from the holder I2. As best shown in Figures 1 and 11, theshank H of the mandrel is provided with a longitudinally extending slotl5 through which a flexible element for my improved seal, representedinthis instance by the solid wire it, is passed. The wire iii may be cutoff, by any suitable means not here shown, to appropriate length forpurposes of the seal and one end i! of the wire may be pushed throughthe slot I5 to lie alongside of and initially parallel with the mandrelit. It will be understood that the expedients just described are merelyone illustrative means of holding the wire and mandrel in this initialrelationship, and that substantially the same result could beaccomplished by hand.

First maintaining the wire and mandrel in the described initialrelationship, I next proceed to loop the end ii of the wire about themandrel, While this might be accomplished by hand, I have illustratedone practical expedient or aid to accomplish this next step in myprocess, here represented by the sleeve it which may carry any suitablehandle element to readily eiiect rotation of the sleeve, a fragment ofwhich is shown in cross-section and indicated by the numeral 99. As hereshown, the sleeve 18 is recessed or bored as at 29 cylindrically tosnugly receive the mandrel Ii] which is also desirably cylindrical. Toreceive the wire also when the mandrel and wire are associated as shown,the bore 26 of the sleeve i8 is enlarged radially and axially as at 2!and as best shown in Figures 2 and 12. Thus by slipping the sleeve l8over the wire and mandrel with the wire located in the slot 2|, and thenrotating the sleeve, while holding the mandrel against rotation, the endll of the wire will be caused to loop about the mandrel as indicated inFigure 3. To assist in locating the wire in the slot 2| I mayadvantageously project the extreme end of the wire slightly beyond themandrel as shown in Figures 1 and 2. Furthermore, by withdrawing thesleeve from the mandrel during the rotation of the sleeve, I may disposethe end of the wire in a plurality of helical turns 22 where loopedabout the mandrel.

After withdrawing the sleeve l8, as shown in Figure 4, I next proceed toassociate the sealing member of my improved seal with the flexiblemember or wire, this sealing member being here represented by thecylindrical slug 23 desirably composed of a malleable or relatively softmetal such as lead. As shown in Figure 5, I slip the slug 23 over themandrel and turns 22 of the wire, the shoulder I4 on the mandrelassisting in locating the slug over the turns of the wire, this shoulderhaving of course previously assisted in forming the first turn of thewire relatively close to the shoulder I4. With the mandrel, wire andslug held in this relationship, I next proceed to form the slug aboutthe wire and mandrel. While this might be done by hand, I advantageouslyprovide compressing expedients such as the complementary jaws 24, 25between which the mandrel, wire and slug are inserted and which arerelatively movable with respect to the mandrel as shown in Figures 6 and10, so as to compress the slug 23 transversely while permitting it toexpand longitudinally.

As best shown in Figure 10, the jaws 24, 25 are desirably somewhatmale-and-female, the upper or male jaw 24 being recessedsemi-cylindrically as at 23 to form the semi-cylindrical portion 21 ofthe lead, the lower or female jaw 25 having the more generallyrectilinear recess 28 forming the somewhat flattened portion 29 of thelead and more particularly the generally flat surface 38 thereon. Uponcompression of the lead as just described, with the mandrel and wireremaining in the relationship shown, the mandrel maintains the helicaldisposition of the wire while at the same time causing the wire to beimbedded in the lead, which is forced by the jaws between the turns ofthe wire and into contact with the mandrel except where the wireintervenes as best shown in Figure 6. Thus when the mandrel iswithdrawn, as shown in Figure 7, the next step in my process, a bore 3|is left in the lead, with the turns 22 of the wire looped about thewalls of the bore 3! and securely anchored in the lead, with theopposite end 32 of the wire it initially free, so that the wire may bebent upon itself and the end 32 freely moved through the bore 3| of thelead, for the purpose presently to be described.

At some stage in the formation of the sealing member to its intermediatestage as indicated by the numeral 33, in accordance with another aspectof my invention, I provide the intermediate sea-ling member 33 with anidentifying mark or marks desirably in the nature of a fi ure formed bya groove or grooves depressed below the normal surface of the lead. Sucha figure is here represented by the concentric circular grooves 34formed in the flat surface 39 of the lead when in its intermediate stage33. This figure may be readily formed during the compression step shownin Figures 6 and 1G by providing one of the jaws, as here shown thefemale jaw 25, with embossments 35 in the shape of two concentriccircles, these embossments, after compression of the parts, leaving theconcentric grooves 34 in the lead.

It will be understood that the intermediate sealing member 33 might beformed as just described from a solid but plastic or malleable slug 23,or might even be formed by casting (in a molten state) the lead or thelike initially about the associated mandrel and wire shown in the stepof Figure 4.

In the next aspect of my invention, the seal is ready to be applied to ameter or the like to prevent unapprehensible access tothe meter. Inaccordance with common practice, certain relatively movable portions ofthe meter housing necessary to be moved to obtain access thereto such asthe hasps 36, 31 having apertures 38 therein, have the wire I6 passedtherethrough, as indicated in Figure 8. This may be done at the centralofiice, or more frequently, by an authorized inspector upon the premisesof the customer where the meter is located. After an inspection, forexample, the. inspector wishes to seal the meter until the nextauthorized inspection, and having passed the wire l6 thru the holes 38in each of the hasps 36, 31 he then passes the free end 32 of the wirethrough the bore 3| in the lead in its intermediate form 33.

Using a conventional compression tool (not necessary to be shown) whichhe carries with him, the inspector then compresses the lead from itsintermediate form 33 to its flattened and final form 39, shown in Fig.9. This compression having taken place in a direction normal to the face33 of the lead, and the lead being expansible in the plane of said face,and the face 30 having expanded as shown in Fig. 9 in the direction ofthe arrows 40, the concentric circles 34 have now become the concentricsomewhat elliptical figures 4!. The lead naturally expands in thisdirection more than in the other, due to the collapsing of bore 3|.inspector also does of course permit expansion of the face 30 forinstance in one direction, as here indicated by arrows 40, but tends torestrict expansion of said face in the transverse directions forinstance as here indicated by the arrows 42, thus preventing the circles34 from taking a merely larger circular form, and definitely changingthe form of the figure from the circles shown in Fig. 8 to the ellipsesor the like, shown in Fig.

9. The compression tool of the inspector also customarily embosses onthe lead a second figure such as the figures 43, which may be theinitials or number of the inspector or might be the initials of theservice company owning the meter.

Upon compression of the sealing member in the intermediate stage 33, toits final sealing stage 39, as shown in Fig. 9, the bore 3| in the leadis substantially entirely closed and not only the initially anchored endl of the wire but now also the previously free end 32 of the wire, areboth securely imbedded in the lead. Preferably the extremity of the freeend 32 projects entirely through the lead as indicated in Fig. 9. As soimbedded the two wires are now not only permanently anchored in thelead, but are intimately interlocked, the end 32 intersectingcontactually the turns 22 of the wire at a number of pointscorresponding to twice the number of turns of the wire. In any event,the two wires are desirably intersecting and interlocln'ng at at Thecompression tool of the so as to be broken and removed and replaced by asimulating seal, without detection. In other words, while it has beenknown to provide seals of peculiar identifying configuration, such asmaking the entire lead member in the form of a cross or a star, forexample, such conspicuously characteristic configurations for the entirelead member are readily perceived by the would-be imitators to bedistinctive and for purposes of identification, and are thereforeclosely imitated by anyone seeking unauthorized access to the meter andwilling to destroy the first seal and replace it with another like it.

In accordance with my invention, in contrast, the identifying mark issubstantially inconspicuous or is thought by the casual observer to beaccidental or merely ornamental and not necessary of imitation, whenattempting to duplicate the seal.

I contemplate as a suitable identifying mark for my purpose anygeometrical figure or the like, that is, a figure having a definitelyalterable appearance, preferably depressed below the surface, or evenraised thereabove. For example, a line or series of parallel lines wouldnot be generally suitable since the mere increase in the length of aline would not be a sufficient alteration in appearance to serve mypurpose.

Furthermore, when the identifying mark in its intermediate stage is inthe form of a circle, for example, as here shown, and this circlebecomes an ellipse or the like in its final form, a would-be imitator ofthe seal would not know without considerable experiment, how to producethe ellipse, and would not readily perceive that it had been produced bymaking the original figure a circle. In any event, he would not know thesize of the original circle, without having seen the lead in itsintermediate stage 33, even though the face 30 were permitted to expandequally in the directions both of the arrows 40 and 42. Moreover, bycausing the figures 43 embossed on the lead by the inspectors compression tool to be superposed or intersecting with the figures 4|, theidentifying marks 4! are rendered still less conspicuous and unlikely tobe imitated by anyone attempting to tamper with the seal.

Obviously, the invention is not limited to the details form and sequenceof steps of operation described above for purposes of illustration.

Such changes may be made as fall within the scope of the followingclaims, as limited by the prior art, without departing from theinvention.

Furthermore, it is not esential that all features of the invention beused conjointly, as various combinations and sub-combinations might beadvantageously employed.

Having described my invention, I claim:

1. As an article of manufacture, a tamperproof seal including a softmetal member having in initial form an identifying figure upon a facethereof formed by a groove depressed below the normal surface of saidface, the member being readily expansible in the plane of said face bycompression in a direction normal to said face whereby the figureremains visible but altered in size or configuration after compression.

2. As an article of manufacture, atamperp-roof seal including a softmetal member having in its iniitial form an identifying figure upon aface thereof formed by a groove depressed below the normal surface ofsaid face the member being thereafter expanded in the plane of said faceby compression in a direction normal to said face over an areamaterially greater than the figure, the figure remaining visible butaltered in configuration after compression, and a second identifyingfigure upon said face formed by said compression of the member.

3. The structure of claim 2 wherein the second figure intersects thefirst mentioned figure.

4. The structure of claim 2 wherein the firstmentioned figure is formedinitially by a substantially circular groove, said figure having theform substantially of an ellipse after the compression of the member andexpansion of said face.

5. The method of providing tamper-proof seals or the like whichcomprises providing a malleable member having a surface with a characterthereon depressed below the plane of said surface and then compressingthe member in a direction transverse to said surface over an areamaterially greater than said character to alter the form of saidcharacter but without substantially defacing the character.

6. The method of providing tamper-proof seals or the like whichcomprises providing a malleable member having a surface with a characterthereon having a face spaced to one side of the plane of said surfaceand partially deforming the member over an area materially greater thansaid character while expanding the member materially more in onetransverse direction than another whereby to alter the form of thecharacter without obliterating it.

RALPH S. PEIRCE.

